Spoofing host's MAC address and existing VMs in Fusion

[vmfh]

After I change the NIC's MAC address and boot existing VMs in Fusion, I get a message asking if I moved or copied them, as if they weren't recognized anymore.

I suppose it's because the adapters have to internally update, but I couldn't find any documentation to this regard.

Regardless of how it actually works, is it possible to force to accept the new MAC address?

[nancyz]

Hi there,

Thanks for using Fusion.

After I change the NIC's MAC address and boot existing VMs in Fusion, I get a message asking if I moved or copied them, as if they weren't recognized anymore.

How did you change the NIC's MAC address?

You could change it in the following steps:

1. Shut down your VM.

2. Open it settings-> Network Adapter.

3. Click the triangle at the bottom to show the advanced option, the you could change the MAC address by editing the MAC address or clicking the 'Generate' button.

Hope this will help.

[vmfh]

Hi nancyz

I change the host's (NIC) not the guest's (vNIC) MAC address and I do it from the command line.

If you have a Mac at hand, you can try with the following and see what I meant in my previous post.

sudo ifconfig en0 ether $(openssl rand -hex 6 | sed 's/\(..\)/\1:/g; s/.$//')

[nancyz]

Hi vmfh,

Thanks for your reply.

I get a message asking if I moved or copied them

The message is expected.  You could dismiss this message by editing the vmx file (but not recommended). Open VM Library, select the VM you want to start up/ resume, holding 'option' key while right the VM in Library, click 'Open config file in editor' , then you could open the vmx file in editor, search the item called 'uuid.loaction', it would be something like uuid.location = "56 4d 68 fe df e1 01 eb-7c 97 4a 65 53 0d 9a ce", then comment the line using '#', save the change. Start up/ resume the VM, you'll not get the copied/moved message.

I change the host's (NIC) not the guest's (vNIC) MAC address and I do it from the command line.

I'm not sure if you still could get your Mac network properly after changing your NIC MAC address.

[vmfh]

Hi nancyz

It works but only if I change the MAC address once. Next time, I have to do it again and for all my VMs. Quite annoying to say the least.

I could script that, but I'm searching for a more permanent solution, like a hidden preference.

Fortunately, it doesn't seem to be a problem for VMs launched from the command line with option nogui and later opening Fusion application, though.

Must uuid.location be bound to the MAC address at all?

The linkage should be between hypervisor and virtual machine, not the physical host, don't you think?

[nancyz]

Hi vmfh,

Thanks for your update. I'll forward your question to our dev and see if he could help.

[vmfh]

Great, thanks so far.

[vmfh]

Hi nancyz

Could you get any feeback from the dev you forward this question to?

[www23456]

We tried on my laptop: 10.10.5 with linux VM. Bridge Or NAT modes are similar.

Using the provided script.

  host en0 take time to get back and VM will detect the dow/up.

  the problem is: even on host after en0 get back the ip, ping remote ip or name sometimes got failed. If the ping from host works, so does from VM.

I guess that might be host related. Basically the VM has same behavior as the host's ping.

what about your case, ping from host? Or can you provide sniffer for vmnet0 bridge/vmnet8 nat when ping working on host, but not on VM?

[vmfh]

www23456‌, hmm, you're posting in the wrong thread, I suppose…

[www23456]

Could you provide the packet trace/pcap for vmnet0 or vmnet8?

[vmfh]

www23456‌you obviously don't understand the problem here, so don't bother to post.

I'm still waiting for a reply from nancyz‌ who contacted a dev in this matter.

[www23456]

maybe try to kill the vmnet-bridge and restart it: /Applications/../vmnet-bridge -d /var/run/ddd.pid vmnet0 <en0> ; then gui->settings->autodetect-->

so basically let the bridge module to reload the host's mac address.

[vmfh · Accepted solution]

Adding the following parameter to the virtual machine's vmx config file solves my problem.

uuid.action = "create"

To solve it more generally you could add it to the template files, I guess, but I haven't tried it.

sudo echo 'uuid.action = "create"' >> '/Applications/VMware Fusion.app/Contents/Resources/template.vmx'